VOCABULARY — Choose the best synonym (same meaning) of the highlighted word, based on the sentence. Sentence: “Even today many people are guided by ABSTRUSE moral values.”

Introduction / Context:
The adjective “abstruse” describes ideas or principles that are difficult to understand because they are complex, highly theoretical, or recondite. In the sentence, it modifies “moral values,” suggesting values that are not readily grasped by most people.

Given Data / Assumptions:

• The word qualifies moral values, not behavior or risk.
• We seek a synonym that focuses on difficulty of understanding.
• We should avoid options that introduce new meanings such as danger, practicality, or rationality.

Concept / Approach:
“Abstruse” aligns closely with “obscure” when “obscure” is used in the sense of hard to understand or not clearly expressed. “Dangerous” and “impracticable” change the dimension from understandability to risk or feasibility. “Irrational” concerns logic, not necessarily comprehensibility.

Step-by-Step Solution:
1) Define the target: abstruse = hard to understand, recondite.2) Compare candidates: obscure = not clear or plain; dangerous = risky; impracticable = not workable; irrational = not logical.3) Select “obscure” as the best match for difficulty of understanding.4) Substitute to confirm: “guided by obscure moral values” preserves the intended meaning.

Verification / Alternative check:
Standard thesauri pair “abstruse” with “recondite,” “obscure,” and “arcane,” reinforcing this choice.

Why Other Options Are Wrong:
A) “dangerous” — relates to risk, not comprehension.B) “impracticable” — feasibility, not clarity.D) “irrational” — logic, not understandability.

Common Pitfalls:
Assuming abstruse means “abstract.” Although related in feel, “abstruse” specifically signals difficulty of comprehension.

Final Answer:
obscure